In osmosis, water freely moves across a membrane from an area of low solute concentration, or hypotonic solution, to one of high solute concentration, or hypertonic solution. When the solute concentration is equal on both sides of the membrane, the solution is said to be "isotonic. Diffusion across a membrane depends on the size and electric charge of molecules.
Smaller molecules diffuse faster than larger molecules. Charged molecules do not diffuse across animal or plant cell membranes; they need to enter or leave cells by other mechanisms, because cell membranes are made up of hydrophobic lipids and repel charged molecules similar to how oil repels vinegar. Osmosis is the flow of water molecules and depends on the particle concentration — not the type of molecule on either side of the membrane.
Diffusion occurs with or without a membrane between two areas of different concentrations of molecules. This movement of water would continue until the water concentration on both sides of the membrane is equal, and will result in a change in volume of the two sides. The side that contains sugar will end up with a larger volume. Water solutions are very important in biology.
When water is mixed with other molecules this mixture is called a solution. Water is the solvent and the dissolved substance is the solute. A solution is characterized by the solute. For example, water and sugar would be characterized as a sugar solution. The classic example used to demonstrate osmosis and osmotic pressure is to immerse red blood cells into sugar solutions of various concentrations.
There are three possible relationships that cells can encounter when placed into a sugar solution. The concentration of solute in the solution can be equal to the concentration of solute in cells. A red blood cell will retain its normal shape in this environment as the amount of water entering the cell is the same as the amount leaving the cell. The concentration of solute in the solution can be greater than the concentration of solute in the cells.
Process Description Substances transported Energy required Diffusion Substances move from a high to a lower concentration down a concentration gradient Carbon dioxide, oxygen, water, food substances, wastes, eg urea No Osmosis Water moves from a high to a lower concentration across a partially permeable membrane and down a concentration gradient Water No Active transport Substances more from low to higher concentration up a concentration gradient Mineral ions into plant roots.
Glucose from the gut into intestinal cells, from where it moves into the blood Yes. Diffusion on the other hand, does not require a membrane to happen.
What are some similarities and differences between osmosis and diffusion? May 2, Explanation: Similarity -They both account for movement of molecules from a region of high concentration to a region of low concentration. Nam D. Explanation: Diffusion and osmosis are processes in which molecules will move from a region of a higher concentration to a region of lower concentration to establish a chemical equilibrium.
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